Ticks, which can carry viruses that cause extreme fever and possibly death, have been found in Seoul, a city government-affiliated environmental institute said Sunday.

A team of researchers released its findings of a field study conducted along 35 popular walkways and rest locations between 2014 and 2016 in Seoul.

The study showed 7,021 ticks were found in 19 locations including riverside parks along the Han River and walkways on Mt. Bukhan.

While no virus-carrying ticks have been found as of yet, caution is still advised as the possibility remains that those that do carry viruses may infest the city, the researchers said.

People bitten by virus-carrying ticks can develop severe fevers with thrombocytopenia syndrome (SFTS), which has a fatality rate as high as 30 percent.

SFTS, following an incubation period of up to two weeks, cause symptoms such as fever, vomiting, diarrhea, drowsiness and organ failure. Currently, no effective medicine is available to treat the disease.

According to the Korea Centers for Disease Control and Prevention (KCDC), the tick-borne disease has killed 42 people this year so far, a sharp increase from 19 last year.